Way back when, I wrote a modular distortion plug called 'Chorrosive'. It has a filter, a chorus unit, and a tube simulation, all of which can be configured using std vst automation - the UI only gives one knob! (classic BetaBugs )

Anyway, there was an error in the chorus, which I corrected.

If you want a manual, you'd have to download the BugPack from the BetaBugs site, if you just want the plug, you can get it here